PASADENA – A jury determined Friday that George Wood Pigman IV was insane when he stabbed his 21-year-old girlfriend to death with barbecue tongs in her San Gabriel apartment in May 2005.

Pigman was convicted of first-degree murder Feb. 23 for killing Eimi Yamada, a Japanese exchange student. Police found Pigman police naked and covered in blood on a rooftop a block away from Yamada’s apartment.

Pigman could have faced a 25-years-to-life term in state prison had jurors determined he was sane at the time of Yamada’s killing. Instead, he is expected to be sentenced to a state mental hospital when he returns to court March 30.

Sandi Gibbons, a spokeswoman for the Los Angeles County District Attorney’s Office, said the verdict was a disappointment.

“We obviously felt that he was sane at the time the crime was committed,” she said. “The jury obviously disagreed with our evidence.”

Jose Colon, one of two public defenders representing Pigman, called the verdict “right and just.”

“From Day One I always thought George suffered from a mental disorder and that the mental disorder figured in the killing of Miss Yamada,” he said.

A psychiatrist who examined Pigman at the Twin Towers jail after he was arrested testified during the trial that he suffers from Bipolar I disorder and was likely in a manic state when he killed Yamada.

Because Pigman will likely be sentenced to a state mental facility, it is possible that he could be declared sane and released before his sentence is up. Colon said the possibility of that outcome was “doubtful.”

“He’ll probably be placed there for the rest of his life, unless he regains his sanity,” he said.

The process for arguing that a patient has regained sanity is extremely difficult, Colon said. If doctors determined Pigman was sane, then a hearing would be held and a judge would decide if he could be released.

“Then potentially they can place him in an outpatient type of housing situation and conceivably release him,” he said.